1. Field of the Invention
This invention relates to hollow conductors having wave permeable rectangular cross-section dielectric material windows received therein in a vacuum tight condition with a metal bandage surrounding the conductor at the level of the window to maintain the window in place while providing a functioning seal.
2. Prior Art
Rectangular cross-section conductors used with inserted rectangular cross-section wave permeable windows of dielectric material are useful in many environments.
Microwave windows of wave permeable dielectric material are known. One such window is described in German Offenlegungsschrift No. 1,931,712 (U.S. Pat. No. 3,646,485). In such prior art embodiments, the ceramic window generally does not have a shape equal to the shape of the hollow conductor or wave guide in which it is received. Thus, one may be rectangular while the other is of an oval shape in order to facilitate the provision of a vacuum tight soldering around the window position. In such constructions, the hollow conductor may be surrounded by two bandage forming half shells which can provide an adequate seal. Such a window formation, while guaranteeing long term sealing and stability of the dielectric material, has a disadvantage in that the cross-sectional change between the window and the adjacent hollow conductor sections adds an undesired reflecting conductor load and requires exactly produced precisely fitting parts.
While the use of rectangular windows are known (see U.S. Pat. No. 3,101,460 to Walker et al. issued Aug. 20, 1963 or Chapter II,D. proc. IEEE, Volume 61, No. 3, 1973 pages 299-330), such windows have been used in arrangements which leave the cross-section of the hollow conductor channel unchanged. Although windows are particularly reflection poor however density problems occur. That is, since the circumferential peripheral surfaces of the window meet at a sharp angle, the mating dimensions of the other members of the assembly which are to be connected together, as by soldering, have to be dimensioned to a high degree of exactness and, in particular, have to be provided with mating sharp angle edges. This can result in the creation of inadmissibly wide gaps or interfering heat displacements.
It would therefore be an advance in the art to provide a microwave conductor-window assembly where both the window and the conductor in which it is received are rectangular in cross-section and wherein the window is sealed in place in the conductor by a vacuum tight metal seal which can be simply affixed and which does not provide for disadvantageously large gaps.